Radar has historically been used for determining the location of and to track objects such as aircrafts or vehicles over relatively great distances. Although this field of use for radar technology still is important new short range applications requiring high precision and low power consumption are now also emerging for the industrial, the medical, the security and the consumer market. Examples of applications include not only determining distances to and positions of nearby objects, but also investigation of material properties such as thickness, size, dielectric properties, material composition etc.
Although radar technology as such is a mature technical field the emerging applications introduces new challenges and requirements for the design of radar systems.
In a typical radar implementation an electromagnetic signal is transmitted and reflected by an object. The reflected signal is received and analyzed. Available technologies include for example pulse-based, Doppler or frequency modulated radars.
Pulse-based radar systems measure the time-of-flight between the transmitter and the receiver for a measurement wavelet. For example, a reflected wavelet may be mixed with a locally generated reference wavelet which is delayed by a known time with respect to the transmitted wavelet. The delay for which the maximum mixing product is achieved corresponds to the time of flight. Due to the pulsed nature of the measurement signals, this type of radar system lends itself for applications where low power consumption is a desirable. However, in order to provide high precision measurements, the delay between the reflected wavelet and the reference wavelet needs to be precisely controlled.